Naturally it's called Four Corners. Nearby,you'll find the Painted Desert with sand of many colors, and the world's largest site of petrified prehistoric rock.

VOA: standard.2010.03.22

And so now I have hydrogens at the four corners of a tetrahedron.

放在碳正四面体,的四个角上。

麻省理工公开课 - 固态化学导论课程节选